CRSCombined insulation bushing

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CRS

Why is a Combined Insulation Bushing better than a conventional porcelain bushing?

A conventional bushing is composed of a conductor bolt (usually brass or copper), a porcelain insulating part, and oil.The fixing system is usually made through a collar flange + some pressure pieces that must be used in order to fix a porcelain flange to a metallic cover.In a Combined Insulation Bushing the conductor bolt is moulded inside an organic insulation resin block; afterwards the primary insulation layer is protected with a silicone rubber coat.

CRS combined insulation bushing

Over 40 years have passed since COMEM began working in the electrical sector and it continues to give great importance to innovation, research and the development of new products. COMEM takes this opportunity to present to (all transformer ’s OEM, Utilities and Engineering Co.) the new Combined Insulation Bushing. This project meets the latest market requirements regarding higher bushing performance, the improved safety of transformers and cost reduction.

Allows you to know the partial discharge level before you actually test the transformer

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Characteristics Porcelain bushing Combined insulation bushingMechanical Porcelain + bolt + collar + pressure pieces Bolt + organic insulator and its moulded clampThermal Porcelain + oil Organic insulator + silicone rubberDielectric Porcelain + oil Organic insulator + its moulded equipotential screenLeaking Porcelain + several gaskets Organic insulator + one gasket

Both combined and porcelain bushings must have proper mechanical, electrical and thermal characteristics to withstand, for many years, any stress related to their transformer application.

The Combined Insulation Bushing is a better choice thanks to the yield it gives for each characteristic as shown in the following summary table:

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The projectThe Combined Insulation Bushing is the result of a combination of the following key aspects: mechanical and electrical technology, the selection of superior raw materials, the interchangeability of the porcelain bushings and the improvement of general safety concerning bushing application.In order to reach our targets, the following simulations were analysed and studied during the bushing design phase:• FEM structure analysis, regarding the max cantilever load

allowed;• Analysis of the electrical field.

Picture no. 1 - Fem 3D electrical field

Picture no. 2 - Fem 3D electrical field

Analysis of the electrical fieldThe simulation to finite elements analysis of the electrical fieldhas been carried out by applying a 100kV continuos voltage.

Description Von Mises stress data from the simulationN/mm2

Material yielding stress by tensile loadN/mm2

Copper bolt 92 190Combined insulation 42 70 - 80Fixing clamp 120 210

Fem structure analysis results

• An internal screen protects the electrical field created by the energised bushing; thanks to the Combined Insulation Bushing design, the level of partial discharges complies with IEC 60137 specifications. At the moment, partial discharges can be neither measured nor reduced in a porcelain bushing.

• In case of an accident or bushing breaking, the Combined Insulation Bushing guarantees no oil will be leaked because there is no oil inside. On the contrary, if a porcelain bushing breaks, this could cause all the oil contained in the conservator to leak (unless somebody uses an automatic cut-off valve).

• The dimensional tolerances allowed for a Combined Insulation Bushing are extremely smaller than the ones allowed for a porcelain bushing.

• The handling and transport of a Combined Insulation Bushing are easier than those one of a porcelain bushing because the insulation material is not fragile.

• The Combined Insulation Bushing is easier and faster to assemble than the porcelain bushing because there are no loose clamps and loose pressure pieces to be used. Furthermore, the Combined Insulation Bushing is interchangeable.

CRS combined insulation bushing

• The Combined Insulation Bushing does not need maintenance, as it has no sealing gaskets,except for those located between the tank cover and bushing clamp.

• The Combined Insulating Bushing has less items to be assembled.

• Furthermore, the Combined Insulation Bushing has many more advantages, for example it uses silicone rubber as its main outer insulation layer making it self-cleaning, flexibile, sturdy.

• There is an M8 thread on the top head of the bolt to lift the Combined Insulation Bushing during assembling.

• The Combined Insulation Bushing is produces in compliance with IEC 60137 and it is fully interchangeable with a conventional porcelain bushing to EN 50180.

• The exceptional quality of selected raw materials allows the Combined Insulation Bushing to be installed in an off-shore environment conforming to ISO 12944.

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Type A B C D D1 D2 D3 F G H Number of sheds Weight

mm mm mm mm mm mm mm mm mm mm Kg24-36kV/1250A 820 235 65 M30x2 Ø225 Ø225 Ø92 470 115 110 9 21.724-36kV/2000A 865 260 85 M42x3 Ø260 Ø240 Ø110 470 135 110 9 25,424-36kV/3150A 865 260 85 M48x3 Ø260 Ø240 Ø110 470 135 110 9 26,252kV/1250A

933 30065 M30x2

Ø250 Ø240 Ø120 498 135 150 930

52kV/2000A 85 M42x3 3352kV/3150A 85 M48x3 3572.5kV/1250A

1163 34565 M30x2

Ø300 Ø290 Ø130 683 135 195 1243.5

72.5kV/2000A 85 M42x3 46.5

Overall dimensions IEC

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Type A B C D D1 D2 D3 F G H Number of sheds Weight

mm mm mm mm mm mm mm mm mm mm Kg24-36kV/5000-6300A 846 206 102 (1) Ø78 Ø280 Ø320 Ø154 498 142 150 8 60(1) air side (oil side there is a washer)

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Identification Technical characteristicsAccording to the standard

Rated voltage

Rated current

Lighting impulse

Dry power frequency

Partial discharges 1.5Um/√3

Creepage distance

Arcing distance

Lee protected line min.

Pollution level Capacitance Tanδ@20kV Operating

loadTemperature range

kV A kV kV pC mm mm mm pF N °C

IEC 60137

24 1250 125 55 10 1360 515 435 P4 65±50.0065

625

-60°C/+120°C *

36 1250 170 77 10 1360 515 435 P4 65±5 1000

242000

125 55 10 1500 515 637 P4 70±5 0,00651000

3150 1575

362000

170 77 10 1500 515 637 P4 70±5 0,00651000

3150 1575

245000

125 55 10 1300 490 503 P4 65±5 0,0065 15756300

365000

170 77 40 1300 490 503 P4 65±5 0,0065 15756300

521250

250 105 40 1630 563 662 P4 70±5 0.004625

2000 10003150 1575

72.51250

325 140 90 (1) 2250 775 807 P4 100±5 0.004625

2000 1000* For -60°C we can deliver a special gasket upon request(1) Lower P.D. values are available upon request

PackingType Dimension mm24-36kV / 1250A 930x315x33524-36kV / 2000-3150A 930x315x33524-36kV / 5000-6300A 930x390x39052-60kV / 1250-3150A

1190x365x40072.5kV / 1250-2000A

Technical data IEC

9

D

M

40

D1

MAX WELDING LINEØ18 mm HEIGHT 2 mm

60°

6 BOLTS

D2

45°

8 BOLTS

Identification Technical characteristicsAccording to the standard

Rated voltage

Rated current

Lighting impulse

Dry power frequency

Partial discharges 1.5Um/√3

Creepage distance

Arcing distance

Lee protected line min.

Pollution level Capacitance Tanδ@20kV Operating

loadTemperature range

kV A kV kV pC mm mm mm pF N °C

IEC 60137

24 1250 125 55 10 1360 515 435 P4 65±50.0065

625

-60°C/+120°C *

36 1250 170 77 10 1360 515 435 P4 65±5 1000

242000

125 55 10 1500 515 637 P4 70±5 0,00651000

3150 1575

362000

170 77 10 1500 515 637 P4 70±5 0,00651000

3150 1575

245000

125 55 10 1300 490 503 P4 65±5 0,0065 15756300

365000

170 77 40 1300 490 503 P4 65±5 0,0065 15756300

521250

250 105 40 1630 563 662 P4 70±5 0.004625

2000 10003150 1575

72.51250

325 140 90 (1) 2250 775 807 P4 100±5 0.004625

2000 1000* For -60°C we can deliver a special gasket upon request(1) Lower P.D. values are available upon request

Type D tank hole mm D1 mm D2 mm D3 mm M No. Of bolts24-36kV / 1250A Ø102 Ø180-Ø185 - - M12 624-36kV / 2000-3150A Ø115 Ø200-Ø205 - - M12 624-36kV / 5000-6300A Ø180 - - Ø280 M12 1052-60kV / 1250-3150A Ø130 Ø200-Ø205 - - M12 672.5kV / 1250-2000A Ø140 - Ø250 - M14 8

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1) MTG: minimum oil level dimension over the current transformer radius1) W: current transformer pocket lenght and distance from flange mountingto minimum oil level

Type A B L R P Q W 2) D MTG 1) Number of sheds Weight

mm/in mm/in mm/in mm/in mm/in mm/in mm/in mm/in Kg/lb25-34.5kV/2000A 86.5/3.406” 626/24.65” 857/33.74” 2”-12UN-2A 159/6.25” 213/8.39” 535/21” 120/4.725” 30/1.18” 7 46/101.425-34.5kV/3000A 86.5/3.406” 626/24.65” 857/33.74” 3”-12UN-2A 159/6.25” 213/8.39” 535/21” 120/4.725” 30/1.18” 7 65/143.3

Overall dimensions IEEE

11

D

M

40

D1

MAX WELDING LINEØ18 mm HEIGHT 2 mm

60°

6 BOLTS

D2

45°

8 BOLTS

Technical data IEEE

Identification Technical characteristicsAccording to the standard

Rated voltage

Rated current

Line-to-ground voltage

Lighting impulse

Dry power frequency

Partial discharges 1.5Um/√3

Creepage distance

Arcing distance

Operating load

Temp. range

Tanδ@20kV

kV A kV kV pC mm/inc mm/inc N/lbf °C

IEEE C57.19.01-2000 IEEE C57.19.00-2004

252000

16 150 75 25 1220/48.03” 450/17.7”890/200

-60°C/120°C *

0.0043000 1300/300

34.52000

22 200 100 25 1220/48.03” 450/17.7”890/200

0.0043150 1300/300

* For -60°C we can deliver a special gasket upon request

PackingType Dimension mm25-34.5kV/2000-3000A 1560x380x380

Type D4 tank hole mm/inc D5 mm/inc O No. Of bolts25-34.5kV/2000A Ø130/5.118” Ø235/9.252” M20 625-34.5kV/3000A Ø130/5.118” Ø235/9.252” M20 6

Identification Capacitance and power factorAccording to the standard

Rated voltage

Rated current

Capacity C1

Capacity C2

Capacity C3

kV A pF pF pF

IEEE C57.19.01-2000 IEEE C57.19.00-2004

252000 251 ±5 83 ±5 19 ±53000 251 ±5 83 ±5 19 ±5

34.52000 251 ±5 83 ±5 19 ±53150 251 ±5 83 ±5 19 ±5

Strada Regionale 11, Signolo 2236054 Montebello Vicentino (VI) - ITALYTel. +39 0444 449311Fax +39 0444 449352 - 440359E-mail: comem@comem.com

www.comem.com

Due to technical product updates, the information contained in this catalogue may be subject to change without notice.

© Copyright 2015 COMEM.All rights reserved.

Ed. 05/2015